Relationship of preoperative NT-pro BNP with clinical, perioperative and prognostic markers in cardiac surgery: Preliminary study results

Abstract

Objective: We aimed to define the relationship of preoperative N-terminal-pro-brain type natriuretic peptide (NT-pro-BNP) testing in routine practice of cardiac surgery with clinical, perioperative variables, surgical outcomes and complications in pediatric and adult cardiac surgery patients. In addition, we assessed relationship of NT-pro-BNP with EuroSCORE II in adult patients undergoing cardiac surgery.   Methods: A total of 48 patients who underwent cardiac surgery in our institution were enrolled into this retrospective  observational cohort study. According to age aspects pediatric (PG, n=20) and adult (AG, n=28) group of patients were separately evaluated. Each group further was categorized into two subgroups (group 1 and 2) on the basis of cut-off points of NT-pro-BNP level (430 and 250pg/ml in adults and children, respectively). Preoperative NT-pro- BNP was obtained from patients. Statistical tests were conducted to reveal differences in clinical and perioperative variables among NT-pro-BNP groups and relationship of the assay with baseline clinical and operative parameters, as well as postoperative outcomes. Results: In adults undergoing cardiac surgery, statistically significant differences  were found between groups with low and high levels of NT-pro-BNP by NYHA classes (I to III, p˂0.001), body mass index (BMI) values (mean (SD) -31.7(3.15) vs 25.9 (3.8) kg/cm2, p=0.017), estimated glomerular filtration rate (eGFR) (111.4 (26.4) vs 77.9 (22.4) ml/min/1.73m2, p=0.036), moderately impaired renal function (20% vs 72.7%, p=0.049), need for inotropes (28.6% vs 86.7%, p=0.006), and mean EuroSCORE II (0.81 (0.19) vs 1.7 (0.5), p=0.008).  There was the positive significant correlation of NT-pro-BNP levels with EuroSCORE II, NYHA class, need for inotropes, renal function and left ventricular (LV) function categories, while its negative correlation was found with BMI, LV ejection fraction and eGFR parameters. In PG – NT-pro-BNP was negatively correlated with age, body surface area, LV end-diastolic and end-systolic dimensions.   Conclusion: In adult patients undergoing cardiac surgery, preoperative NT-pro-BNP level correlated well with several baseline and clinical-operative parameters, including BMI, renal and LV function, NYHA class, need for inotropes support, and EuroSCORE II.   Further studies are needed to define its exact diagnostic and prognostic significance in pediatric patients.